Collagen, the major structural protein of the soft and hard periodontal tissues, is disorganized and destroyed during periodontal disease. The objectives of this study are to study the effects of inflammation and diabetes (a relatively common systemic factor that accelerates periodontal breakdown) on gingival collagen metabolism in rats and humans. More specifically, the animal studies will examine diabetic alterations in (1) gingival collagen biosynthesis, including prolyl and lysyl hydroxylase activity and the formation of H3-hydroxyproline in vivo; (2) the relative amounts of type I and type III collagens in gingiva; (3) gingival collagen maturation, including lysyloxidase activity and the solubility of H3-hydroxyproline labeled collagen formed in vivo. In addition, germ-free rats will be made diabetic to determine whether the diabetes-induced changes in gingival collagen metabolism are a direct effect, mediated by alterations in tissue metabolism, or an indirect effect, resulting from an altered oral microflora. Gingival tissue from systemically-normal and diabetic human subjects (removed during periodontal surgery for therapeutic reasons) will be analyzed for soluble and insoluble collagen content; other samples will be cultured to examine collagen turnover and collagenase activity in vitro. Gingival fluid collagenase activity will be monitored in these subjects, before and at various times after surgery and will be correlated to collagen changes in the adjacent gingival tissues.